I have an older Enterprise Vault setup, version 188.8.131.525. This implementation predates me and had pretty much been abandoned before I started as well. It was still running though and access to the archives were functional. They used the Exchange archiving as well as File archiving. The file archiving was still functional from the standpoint of retrieving archived files with the placeholder service on the file server. The Vault server is an a WIndows 2003 system, but the archives themselves were put on a Buffalo Terastation Pro.
As I mentioned, everything was working fine, that is until we moved offices. Not everything was moved all at once though. The SQL server was moved to a datacenter months before and everything was accessible. The server was moved to the datacenter during the Superstorm Sandy outages (needed it for other services) but the Terastation remained behind. We did change the IP address of the terastation after we got power back, but still archives were accessible. Finally, the Terastation was moved to the datacenter when we moved our office, but no the archives are not able to be retrieved.
At this point, the Vault server event logs indicate an unknown username and/or password to the locations of the cab files, but if I log in as the service account I can get to those files fine as well as open them. I honestly can't tell if the issue is the Enterprise Vault or with the Terastation.